52 research outputs found
Investigation on the basin-scale factors of bedrock shoals distribution in the Flint River, Georgia, USA
Bedrock outcrops create shoaled sections in many rivers of the eastern United States. Bedrock shoals can consist of a variety of channel morphologies and lithologies and are important forms of river habitat by having higher species richness than other locations along the same river. Despite their ecological significance, the system-scale factors that determine their occurrence in rivers are not well understood. In this study, shoaled and non-shoaled sites along the length of the upper Flint River, Georgia, were analyzed to determine the factors responsible for the presence of shoals. Strike-flow ratio, rock integrity, confinement ratio, unit stream power, and geologic dip were selected as possible variables based on existing literature and observations on bedrock shoals and general bedrock morphology. The results of a logistic regression showed that confinement ratio and unit stream power were the most statistically significant predictors of a river reach’s shoal status (p=0.001 and 0.014, respectively), suggesting that variables comprising the driving forces in the Flint River currently dominate system-scale expression of channel morphology. A predictive equation developed from the binary logistic regression analysis correctly classified 80% of known shoaled sites as “shoaled locations” in the watershed and 60% of known non-shoaled sites as “non-shoaled locations” in the watershed. While these results are promising and suggest that system-scale heterogeneity of channel morphology may be controlled by spatial variability of confinement ratio and unit stream power, there is room for improvement, particularly in regard to correct classification of non-shoaled locations. In comparing the findings of this research to those previously made on bedrock shoal occurrence in the Cahaba River, Alabama (Bishop, 2013) – visually similar to the Flint River – questions arise concerning the prevailing view of how dynamic equilibrium operates in fluvial geomorphic systems. Although the Cahaba and Flint Rivers contain bedrock shoal morphologies for long expanses, the occurrence of bedrock shoals in the Flint River are controlled by driving forces, while bedrock shoals in the Cahaba River are controlled by resisting forces. This finding supports the idea that dynamic equilibrium, a state of balance between driving and resisting forces, may be temporally and spatially limited in geomorphic systems. (Published By University of Alabama Libraries
Lake tuscaloosa and the North Tiver: an analysis, and plans to improve, water quality
Lake Tuscaloosa and the North River of Tuscaloosa, Alabama are on the Environmental Protection Agency's (EPA) 303 (d) list. The EPA's 303 (d) list is used to identify waterbodies that do not meet federal standards originally set by the Clean Water Act (CWA) of 1972. Lake Tuscaloosa and the North River are listed four times, three times for mercury and once for nutrient siltation (habitat alteration) on Alabama's 2010 303 (d) list. Studies have identified E. coli and sedimentation as issues affecting the water quality of the North River Watershed. The goal of this research was two-fold: 1. Investigate the importance and effectiveness of the 303 (d) list as a tool to improve water quality, and 2. Examine what plans have been developed and are being developed to improve the water quality of Lake Tuscaloosa and the North River to remove them from the 303 (d) list. These goals were achieved by examining the policies surrounding the issue; evaluating the current plans and studies that have identified factors involved with the water quality of Lake Tuscaloosa and the North River; conducting a Z score analysis of sampled data over the past thirteen years; conducting a land use comparison of the North River Watershed from 2000 and 2011; and identifying the stakeholders involved with the 303 (d) process in Alabama. The results of these analyses revealed that, for the chemicals tested, water quality was stable throughout the time span of sampling for all variables except aluminum, chloride, and sodium, all of which increased over time. These increases corresponded with a decline of 1.07% in forested land use and an increase in cropland and pasture land use of 0.73% from 2000 to 2011. It was also discovered that re-testing for mercury had not occurred, which will make it difficult to decide if delisting would be appropriate. Overall, this research demonstrated a need for stronger regulations within the 303 (d) list and identified factors such as the permitting process, as criterion that need to be added to the 303 (d) to improve its effectiveness. (Published By University of Alabama Libraries
Modeling and analyzing land use and land cover change in metropolitan Birmingham area using landsat TM, OLI data
The Birmingham Metropolitan Area experienced land use land cover (LULC) change over the last three decades, such as the development of urban area, the development of transportation system, deforestation, and rise of population. The main purpose of the thesis is to model and analyze the LULC change through last three decades in Birmingham area, and also simulate the LULC in next three decades. Landsat 5 Thematic Mapper (TM) and Landsat 8 Operational Land Imager (OLI) data from U.S. Geological Survey (USGS) is used for investigating the LULC in Birmingham area. Supervised Classification is used; the maximum overall accuracy is 86.33%. Drivers such as transportation, topographic measures, population and income, location measures are analyzed. Remote sensing indices are also derived from Landsat data, such as NDVI, NDBI, MNDWI, and LST. Pearson's Correlation test is run among the LULC proportion, drivers within counties and census tracts. Finally, the cellular automation model SLEUTH is used to simulate the future pattern of LULC. The results shows the Birmingham experienced a significant LULC change in last three decades. Transportation and slope are two main factors in terms of LULC change. In summary, the thesis completes a systematic LULC classification in Birmingham area in last three decades, and uses different methods to model and analyze LULC and eventually simulate the LULC pattern in next three decades. (Published By University of Alabama Libraries
Hydro-geomorphological influences on plant patch density and distribution in bedrock shoal habitats of the Cahaba River, AL
Abstract There is a growing body of research that examines bedrock channels. Despite this, biotic-abiotic interactions remain a topic mostly addressed in alluvial systems. This research seeks to identify patch-scale hydro-geomorphic factors operating at the patch-scale in bedrock shoals of the Cahaba River (AL) that help determine the distribution of the emergent aquatic macrophyte, Justicia americana. Macrophyte patch density (number of stems/m2) and percent bedrock void surface area (rock surface area/m2 occupied by joints, fractures, and potholes) were measured (n = 24) using stem counts and underwater photography, respectively. One-dimensional hydrologic modeling (HEC-RAS 4.1.0) was completed for one cross-section within a shoal to examine whether velocity and channel depth are controlling variables for macrophyte patch density. A Pearson's Correlation test between bedrock surface void area and stem density demonstrated a statistically significant positive correlation (r=.665, p=0.01). Results of an independent t-test between the velocity and depth model outputs for within and outside plant patches showed a significant difference in average velocity (p =0.011) and depth (p = 0.001) between the two types of locations across discharges, ranging from 7 m3/sec to 226 m3/sec. These results suggest that the amount of void space present in bedrock surfaces and localized depth and velocity help control the macrophyte patch density, and by extension, the distribution of macrophytes in bedrock shoal complexes. The utility of geomorphology in explaining patch-scale habitat heterogeneity in this study demonstrates potential to use geomorphology to explain macrophyte habitat heterogeneity at reach and system-scales and highlights the need for more research that helps understand biotic-abiotic interactions in bedrock fluvial systems. (Published By University of Alabama Libraries
Geomorphic response to tornado impact in Abrams Creek, Smoky Mountains National Park, Tennessee
Tornadoes have the potential to alter river geomorphology. Considering the frequency and intensity of tornado events in the U.S., it is likely that tornadoes are an unaccounted source of natural disturbance in fluvial systems. This study reviews the potential effects of tornado impact on rivers and presents findings from a study of tornado impacts conducted in Abrams Creek located in the Great Smoky Mountains National Park, Tennessee. In April 2011, an EF4 tornado touched down in Abrams Creek watershed. The National Parks Service left all the damage untouched. I studied two ~1 km stream reaches: an upstream reach directly impacted by the tornado and a downstream reach which was not. I measured the morphology of pools, including maximum length, average width, and residual pool depth, under base flow conditions (July-October 2015) in both study reaches and compared them using a t-test. Statistical differences in residual pool depth existed between the upstream and downstream reach (p value = .027). This difference is likely the result of increased hydraulic erosion in the upstream reach and an influx of sediment in the downstream reach. The results of this study suggest tornadoes can and do affect river geomorphology, with their effects persisting years after the event. The geomorphic disturbance initiated by tornadoes have short and long-term implications for in-stream ecological functions. A better understanding of the geomorphic and ecological implications following a tornado could help guide management strategies and decisions for river conservation and restoration efforts. (Published By University of Alabama Libraries
Urban growth monitoring of Birmingham, AL using Landsat MSS and TM imagery
Monitoring urban growth and change in land-use/land-cover in metropolitan areas is of critical interest in the twenty-first century. It is of utmost importance to those who study urban and metropolitan dynamics and to individuals who are in resource management. This research is focused on monitoring urban spatial growth or urbanization and land-use/land-cover changes in the Birmingham, Alabama, Metropolitan Area. This research will analyze urban growth and land-use/land-cover change over a thirty-four period from 1974 to 2008. This research takes place in the counties of Jefferson and Shelby, which is the core of the Birmingham, Alabama, Metropolitan Area. Landsat images from four years, one for each decade in the thirty-four year period, which were also very close to anniversary dates, were obtained to monitor the urban growth and land-use/land-cover change. GIS and remote sensing methods were utilized to achieve the research goal. (Published By University of Alabama Libraries
The impact of storm surge from successive hurricanes on the Alabama beach mouse population
Global environmental change affects plants and animals by changing their distributions and phenology, and altering ecosystem functions. Already endangered plants and animals subject to these changes may be more vulnerable to extinction. It is important to understand how species are likely to respond to environment change so that proper steps can be taken to protect them in the future. This thesis observes the case of the Alabama beach mouse (Peromyscus polionotus ammobates), a population endangered initially because of habitat loss and fragmentation. The Alabama beach mouse population likely will be negatively affected by environmental change through increased hurricane frequency and intensity. Using Alabama beach mouse trapping data provided by the U.S. Fish and Wildlife Service, I examined the storm surge effects of Hurricanes Ivan and Katrina on mouse populations before, during, and after these hurricanes. Analysis of the data was performed through contingency tables and Wilcoxon signed-rank tests. The results of the analysis show that the Alabama beach mouse has the ability to survive hurricanes in the future, if they are not successive. The Alabama beach mouse possesses certain traits that make it more vulnerable to extinction in the near future by environmental change, such as greater than normal disturbances both from humans (i.e. habitat loss and fragmentation) and the natural environment (i.e. hurricanes and climate change.) I postulate that the Alabama beach mouse population will be completely extirpated from Gulf Shores in the event of successive major hurricanes in the future. The intended result of this study is not only to find out how the Alabama beach mouse may be affected by global environmental change, but to contribute to the literature concerning the species to be used in effective management strategies. (Published By University of Alabama Libraries
Patterns of riparian and in-stream large woody debris across contrasting stand ages in a southern Appalachian forest
Large woody debris (LWD) has been credited as an important structural and functional component of riparian and in-stream ecosystems. LWD that recruits from riparian zones into stream bankfull margins is crucial in understanding the connectivity between the two ecosystems. The amount of riparian zone and in-stream LWD is closely linked to the time since last disturbance and successional patterns following that disturbance or disturbance events. However, this relationship is poorly understood in southern Appalachian landscapes. I analyzed the amount and volume of LWD in stands of contrasting establishment ages in the Sipsey Wilderness of the Bankhead National Forest, Alabama and the large woody debris loading in streams that were contained within three establishment classes. The establishment classes span 60 years (pre-1900s to 1950s) and incorporate three stages of forest development: stem exclusion, understory reinitiation, and understory reinitiation that is transitioning into complex. The most often cited pattern of LWD loading across forest ages is a parabola shape. However the abundance and volume of LWD across the establishment classes in the study area followed a bell shape pattern with the highest amount and volume of riparian zone LWD in the 1930s age class. In this establishment class mean volume of LWD per plot was 5.62 m3 ± 1.17 SE compared to 4.26 m3 ± 0.60 SE in the pre-1900s establishment class and 5.09 m3 ± 0.59 SE in the 1950s establishment class. Mean density and mean volume of riparian zone LWD per plot did not significantly differ across the chronosequence. The mean volume of in-stream LWD followed the same bell shape pattern with the highest mean volume of in-stream LWD per plot also occurring in the 1930s establishment class (2.50 m3 ± 0.72 SE). However, there was no significant difference in the density or volume of in-stream LWD across the chronosequence. Not only does this study provide specific LWD abundance and volume for specific stand ages but it also can provide baseline data for mature Quercus stands. In addition, my research begins to explore how stand dynamics influences LWD in a southern Appalachian system. (Published By University of Alabama Libraries
Exploring location and accessibility relationships between manufactured housing and banking facilities in Tuscaloosa County, Alabama
This study has explored location and accessibility relationships between manufactured housing (also referred to as mobile homes, manufactured homes, or trailers) and banking facilities in Tuscaloosa County, Alabama. The main research objective was to examine the relative location of manufactured housing and banking facilities. Additional research objectives included determining the demographic characteristics of mobile home residents and finding out whether or not these residents have access to banking facilities. The study showed that whereas manufactured homes tend to be located in outlying census tracts or in the central part of the county outside city limits, banking facilities are located in the central part of the county within city limits. A Geographical Information System (GIS) suitability analysis showed that overall, less urbanized areas are suitable for the location of manufactured housing units in Tuscaloosa County. These trailers have kept out of the more urbanized locations by zoning restrictions. Statistical analyses showed that the number of industrial establishments and population density are strongly correlated with the number of branches of identified banking facilities, with the number of industrial establishments having the strongest correlation. A spatial mismatch was found between the locations of manufactured housing and banking facilities. Less urbanized areas where mobile homes are located were found to have low population densities, low per capita incomes, and low levels of competitiveness, while more urbanized areas where banking facilities are located were found to have high population densities, high per capita incomes, and high levels of competitiveness. From the survey of mobile home residents carried out as part of this research, it was evident that a majority of household heads (approximately 57%) are between the ages of 46 and 65 years, while 14% are 65+ years old. It was also found that approximately 58% of household heads are working, while 42% are not working. All the respondents in the survey use banking services, with a majority using credit unions. An overwhelming 91% of respondents use loans, while 60% of those who use loans have gone in for a home or home improvement loan (either alone or together with other loans). Based on the results of the survey, it was fair to conclude that notwithstanding the spatial mismatch between the locations of manufactured housing and banking facilities, residents of manufactured housing have access to banking facilities in accordance with the Community Reinvestment Act (CRA) of 1977. This implies that one does not necessarily have to be located in close proximity to a banking facility in order to access banking services, as most banks have adopted more technologically advanced ways of dealing with their customers. Also, with space-time accessibility measures, where people work or shop could be a much more useful way of assessing whether or not they have access to banking facilities. However, in terms of aggregate accessibility which is based on points such as homes or zones, or topological accessibility which is based on travel distance or time, manufactured housing residents are placed at a disadvantage relative to residents of site-built homes when it comes to accessing banking facilities. (Published By University of Alabama Libraries
An examination of historic wetland loss in Northern Mississippi floodplains using general land office surveys
Prior to European settlement of America in the late 16th century, a relatively pristine environment existed on the North American continent. Since that time, landscape-altering processes such as logging, deforestation for agricultural cultivation, channelization, and the removal of natural ecosystems engineers such as the beaver (Castor canadensis) have left little of its natural state unchanged. Alluvial floodplains within the upper Gulf Coastal Plain of Mississippi and the bottomland hardwoods that occupy them are especially sensitive to change, already being naturally dynamic environments in which loose sedimentary soil participates in a perpetual cycle of deposition and erosion as the main river channel meanders across their broad valleys. These changes result in microhabitats with varying degrees of inundation, rates of deposition, and elevation. This thesis attempts to reconstruct the pre-European settlement ecology of northern Mississippi alluvial floodplains through the use of General Land Office (GLO) survey records of the area from the early 19th century. A specific effort will be made to detect wetland environments based upon a surveyor's recorded bearing trees and line descriptions. A bearing tree, or a witness tree, is a tree that is physically marked by a surveyor to indicate a nearby survey corner. Geographic data given by each surveyor (e.g., section, township, range, and distance in chains from each section corner) allow for the relatively accurate plotting of each bearing tree within a Geographic Information System. Digitization of data allows for historical GLO data to be analyzed by location and relation to modern datasets to detect land use change and anthropogenic disturbance in the study area. Specific attention will be paid to two highly flood tolerant species, Taxodium distichum and Nyssa aquatica, to detect these changes for wetland environments. (Published By University of Alabama Libraries
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